Electric switch



March 4, 1930. H. l.. VAN VALKENBURG 1,749,200

ELECTRIC SWITCH Filed April 27, 1925 2 sheds-sheet 1 March 4, 1930. H. l.. VAN VALKENBURG 1,749,200

ELECTRICy SWITCH Filed April 27, 1925 2 sheets-sheet 2 w n L@ C.

QW/720572 Vfm/ lZe//z'wg L@ @Zava/u v @M4 Patented Mar.v 4, 1930 l A1,749,200v

,y )UNITED 'STATES PTENT OFFICE HII'IRMIOl-il'A LIV-AN VALKENBURG, OF MILWAUKEE, WISCONSIN, ASSIGNOR, -BY IIESNE ASSIGNMENTS, TO SQUARE D COMPANY, OF DETROIT, MICHIGAN, A CORPORATION i OF MICHIGAN n f ELEc'rRIo SWITCH Application led April 2f?, 1925. Serial No. 25,993.

My invention relates to electric switches, and especially to switch fingers and their mountings. Switches of this general type are frequently used in startersfor direct current motors, and for the sake of illustration I' have chosen to illustrate the invention as 'embodied in a direct current motor starter.

ASuch starters employ a plurality of fingers which are brought into action consecutivelyto cutout resistance as the motor accelerates. For various reasons these vfingers become damaged and need to `be replaced from time to time. vAn object of my invention is to provide a construction such that the fingers kind. In other words, itl is my purpose to;

l ratus; Broadly speaking, this characteristic;

)In apparatus embodying my invent'on the will be individually spring-pressed and will be secure in their position in the apparatus, but at the same time may be readily removed or replaced without the aid of tools-of` any provide switch lingers fwhich may be removed or replaced individually with a minimum of eiiort and which will nevertheless maintain their position securely. in the appais not new, but my object is to provide an improved and simplified construction which the general object may be attaine contact fingers may be taken out b merely lifting them oi their` fulcrums and pushing back the springs by which they are held seated:

Another object is to provide a support for the 'contact fingers of special simplicity andeiectiveness and one which will also promote the security with which the fingers will mainl tain their position on their fulcrum when in fingers.

I accomplish my objects by the mechanism illustrated in the accompanying drawings in which Figure 1 is'a front view ofy my device in. the I'lr'orm of a motor starter embodying -the invention. In this view the electromagnetic coil and associated parts are shown chiefly 1n axial section.

Figure 2 is a side elevation looking toward the left in Figure 1.

Figure 3 is a sectional view on the line 3-3 Figure 1.

Figure 4 is a side elevation partly in section showing an individual contact finger and .its mountings.

Figure 5 is a top plan view ofthe parts shown in Fig. 4.

Figure 6 is a perspective view of a coil spring and associated elements for backing up a contact finger.

lFigure 7 is a perspective view of a contact finger.

Figure 81s .a perspective viewof one of the brackets in whichthe fingers are supported.

Like numerals denote like .parts throughout the several views.

In the form selected to illustrate the invention the parts are mounted on a panel 10 of insulating material. A movable contact bar/ 12 is arranged horizontall beneath the contact fingers and is contrcled vertically by means of a' rod 14 secured to a plunger 16 vertically -movable within an electromagnetic coil 18. The upward movement is retarded by means of a dash pot which includes a piston 22 which cooperates with the plunger 16and moves within a cylinder 2O containing oil or other retarding fluid. The coil an dash pot are secured to the panel by two cooperating brackets 24, 26. Above the con tact fingers, which will presently be described, are resistance coils 30 which are secured to the panel 10 by suitable brackets 32 As the parts thus .far described are not of the essence of the present invention they need not be'herein described in detail. Parts sim- 'ilar to them are shown in my prior Patent N o. 1,266,642. It is sufiicient for the present' purpose to say that whenvthe coil 18 1s energized thecontact bar 12 willbe gradually elevated to engage the contact fingers successively. Y n

eferring now to the parts more intimatel concerned with the invention, the contact fiyngers 36 are here shown to be four in number, although the number' may be varied without departing from the spirit of the invention. They are all alike, that is, ofY standard pattern, the purpose being to reduce the cost of manufacture and the number of parts which must be kept in stock for repair purposes. The configuration of these fingers is shown in perspective in Figure v7, each finger consisting of va comparatively straight arm or bar of suitable conductive material and provided at its outer or free end with a contact portion or contactor 38 adapted to covpe'rate with the contact bar 12 previouslyl mentioned. l

' At its inner end each finger is recessed on its under side, it being desirable that the recess -be deep enough to enable the fingerl to hold its seat firmly on its support. In the specific form shown each finger has a hook consisting of 'an arched portion 40 adapted to Iseat upon a fulcrum pin 42 and a tail 44 which projects below or forward from the plane of the finger and serves the dual purpose of insuring the position of the finger on the pln and that of a'stop for limiting the movement of the finger under the action of they coiled -compression spring 46 hereinafter again referred to. The tail44 cooperates with a sta! tionary arm 48 formingcpart of the supporting bracket 50. Between its ends each finger has a hump 54 having an aperture 56 in the middle which accommodates the reduced lower end 58 ofthe pin 60 which assists in, yieldingly holding the Contact fingers in position. This may be said to constitute a pin and socket connectionbetween the guide p in and the finger. 'A head 62 is formed vnear the vlower end 'of the piny and serves as an abutment against which the hump 54 bears and also as a collar or shoulder for supporting the cap 64 on which the lower end of the spring 46 seats A similar cap 66 seats upon the top of the spring, these capsbeing apertured to permit the pin l to slide freely through them. It is desirable that -each pin.l 60 be pee'ned'or riveted4 over at the top to prevent the uppercap from coming' off'. Thismakes a unit construtcion, that is, each spring'and its-associated parts keep together and'canbe handled as a unit;

The hump 54 above'mentioned, on which the pin bears, is located nearer thel fulcrum pin 42 than it is to the other end of the finger. By thus bringing thepressure of the spring near the fulcrum point'the pressure of the finger upon the fulcruni is increased to such an extentthat the usual auxiliary shunt or .connecting-wire is unnecessary. The use of such a wire is shownin my aforesaid patent.

Another advantage of this construction in which the spring bears so closely to the ful-- crumis lthat it permits the finger to have a wide' range of movement. l

The bracket 50 previously mentioned vhas an arm which projects forward from the top and is bifurcated at the outer end, having a slot 72 which 'accommodates pin 60.

Flanges 7 4. depend from the outer bifurcated i ends of the armand these retain the upper addition to the stop arm 48 and upper arm 70 previously described the bracket hastwo forward projecting Wings 76 which are arranged vertically and form a support for the fulcrum pin 42. These wings are spaced apart sufficientlyv tofreely accommodate the contact finger between-them, but-at the same time prevent muchlateralplay. These Wings also protect the finge'gsagainst any blow from the side which might vtend to dislodge the finger from the fulcrumon'which it rides. In

other words-the bracket practically constitutes a housing and by preference is formed of a Vsingle piece of sheet metal. Each bracket is securedto the insulating panel 10 by a screw 80 which passes through thepanel and at the outer end makes electric contact with a strap 82. These straps are connected to the .i

different resistance coils 30 1and operate in the usual manner,

In accordance with common practice the switch fingersnormally standat different elevations, and this -is accomplished in my apparatus by bending the stop arms 48 to different angles as clearly `illustrated in Figure 2.

The operation will now be 'readilyunderstood. After the parts have been assembled as illustrated in Figures 1 and 2, if the coil 18 is energized the plunger 16 will'be caused to rise gradually under the retarding influence of the dash' pot and bring the contact bar v12 'first into engagement with the lowermost contact finger andthen successively into' Contact with the adjacentfingers, thus to cut out the resistance offered by the coils 30. If

with the-finger or the finger may be loweredl away from the spring device, for it willbe noted that said device Vmakes one-Way engagement contact with the finger, merely resting upon it and not being in any way fastenedto it. The spring device simply makes end contact withthe back of the finger atone end, and

the under side of arm' 7 O at the other end, and V consequently the sprin device may be removed from the bracket y merely lowering it away from the latter after the finger has been removed. There is no danger of the partsbef coming disassembled because there is a pin and socket connection between the guide pin 60 and the finger, and similar engagement between the upper cap 66 and the upper horizontal arm 70. The upper cap normally prevents the pin from sliding out of slot 72 but the spring device may be readily taken out even though the contact finger is present, for

by lowering the capV .66sufiiciently to clear the lower end of the flanges 7 4 the pin 60m'ay be slid out of slot 72. Thus it will be evident that the ldevice is extremely simple inconstruction, vand no nuts, screws orcotter pins need be removed as a prerequisite to taking the elements apart.y

I do not herein claim the'form of bracket by which the solenoid 18 is supported, as this forms the subject of a separate application filed by me on the 27th dayy of May, 1925, Serial No. 33,095.

yHaving thusdescribed 4my invention what I claim as new and desire to secure by Letters Patentis:

1. -An electric switch having an electrically j energized stationaryv support and a contact 30Y finger, one having an open concavity and the other a portion projecting into it, whereby the finger" is pivotally supported, may be I .lifted off, and isenergized, the front side of the finger making contact withthe fulcruni and having a main contact surface, an abutment fixed relatively to the fulcruin, a spring engaging the finger betweenits ends for urg ing it forward toward acting position and to maintain it seated on the fulcrum, and a tail .15 hook the tail offwhich extends substantiallyV p of the finge-r about its fulcrum.A 1 2. An electric switchlhaving a cylindrical fulcrum, acontact finger in the form of a at right angles to the length of the'finger, Well beyond the fulcrum, the end of the finger opposite ,to the hooked end having a contact surface on the frontside and the hooked end 5o having al concavity on its front side adjacent to the tail of the hook, said concavity facing forward land being. of a diameter fully as great as the diameter of the fulcrum whereby the finger may be lifted off, a spring acting 53. upon the finger ,between its ends for pressing co extent to which -thefinger may be the finger forward" toward the fulcruin 'and toward 'the part to be electrically'contacted,

and astationaryabutment for the outer suraxis, means acting upon the fingers lbetween their ends in a direction to urge them toward the fulcrum, the tail at the hooked end of the finger also projecting in a forward direction well beyond the fulcrum, and a stationary abutment havingv a plurality of arms arranged side by side opposite to the individual fingers, in position to engage the outer side of the tailsthereof, the fingers being of uniform configuration and the arms being bent with the arm and the finger whereby the spring device may be lifted out as a unit, and when removed permits the finger to be lifted ofi its fulcrum.

5. An electrical switch having a cylindrical current carrying fulcrum, a contact finger having a wide mouth concavity seating upon the fulcrum whereby the finger may be lifted away from it for detachment, the acting surface of the contact finger being on the forward side, and the concavity facing forward, a stationary arm behind the finger and spaced fromrit, and a single, self-contained freely removable compression spring interposed between the arm and the finger and making one# way engagement contact with each of them, whereby the spring may be lift-ed out of the assembly and the finger may be lifted off the fulcrum when the spring is removed.

6. An electric switch having a contact fin l40 at the inner endfof the finger, for engaging lliger with a contact surface on the front at one A the abutment to limit the forward movement. Rend and a wide m0th concavity facing the "front at the other end, a cylindrical fulcrum on which ythe concavity seats, a bracket in the form of a hOuSing,said bracket having .forward projecting, vertically 'arranged wings for supporting theffulcrum'and guarding the finger from the sides, an arm projecting for-V ward'over said wings, a spring interposed between the top of the finger and the under side ofthe arm, and a removable self-contained unitary spring device making one-way engagement contact with the baclr of the finger and with the under side of the arm and held in place solely by. themw ereby lthc spring device can be lifted out of he assem-v blyv and the finger may be lifted off the fulcrum.

7. An electric switch having a stationary arm, a fulcrum a contact" finger pivotally mounted on it, and a unitary, self-contained spring device interposed between the arm and the fingen'` for holding the latter seated upon the fulcrum, said spring device comprising a pin, a helical compession spring surrounding it,'the spring ing anchored at one endl iso i to the pin and at the other end free to slide relatively to it, and means for preventingthe free end of the spring from slipping past the free end of the pin.

8. An electric switch having a stationary fulcrum, a contact finger "having a widemouth concavity on the forward side, seating upon the fulcrum whereby it may bev lifted 01T from it, a stationary arm behind the fulcrum, and a self-contained, unitary, compressive spring device interposed between thearm and the finger for pressing the finger forward toward acting position and pressing it firmly against the fulcrum, said spring de- 15 vice comprising a pin, ahelicalv compression f for urging said contact finger ina forward direction, said spring device comprising a pin making one way engagement Contact with said finger and passing slidably through said abutment,` a' coiled spring surrounding the pin and anchored to it at one end, a cap en-v gaging the other end of the spring the cap being slidable along the pin and adapted to engage the abutment, and means at the end of the pinv farthest from the Contact finger for preventing the cap fromslipping over the end of it, all the equipment of the pin lying on the same side of the Contact finger where- -by the spring device is self-contained and removable as a unit. 40 10. An'electric switch having a lift-outcontact finger, at one end of which a concavity is formed which opens towa/rd thefront, the other end of the finger having a contact-making surface onthe front, a cylindrical current-'carrying fulcrum on which the concave portion of the finger seats, a single, loose, detachable spring acting upon the finger between its er'ids for urging it forward toward act-ing position and for urging the concave portion toward the fulcrum to kee it seated andobtain good electrical contact w ereby the fulcrum may be the gsole source of electrical`l energy, the concavity having anopening of sufficient diameter to permit the fingerv to be lifted off the fulcrum, and means for electrically energizing the fulcrum.

11. An electric switch having a loose, vdetachable contactfinger with a contact surface on the front at one end and a wide-mouth 30 concavityfaci'ng the frontv at the other end,

seats, means for electrically energizing said fulcrum, a bracket in the formof a housing,

.5 said bracket having. forward projecting, vera cylindrical fulcrum on which the concavity tically arranged wings for supporting they fulcrum and guarding the 'finger from the sides, an arm projecting forward over said wings, a spring interposed between the top of the nger andthe underside of the arm, and a loose, detachable self-contained unitary spring device making one-way engagement contact with the back ofthe finger and with the under side of the arm whereby the spring device can be lifted out of theassembly and the finger .may be lifted off the fulcrum, without unfastening any fastening devices.

12. An electric switch-having a support, a

.contact finger pivoted upon said support,'a

guide pin bearing upon the back of the finger and having a pin and socket connection therewith, a spring for urging the pintoward the finger, and an arm rigid with said su port and overlying the top of tliespring, said) being bifurcated for accommodating the pin and having a flange'at the outer end of the bifurcations for retaining the spring.

13. An electric switch having a stationary support and a contact' finger, onehaving an arm e `open cavity and the other `a projection ex- 14. A switch having an electrically ener-` l gized support and a contact finger, one having an open cavity and the other having av projection seating therein whereby the finger is lfreely removable from itssupport and pivotally supported thereby, and a single sprin urging the finger toward acting position an also toward its support whereby to insure good electrical contact with said support, said pivotal connectionforming the current carrying connection between ythe-finger and its support.

15. A switchv havingan electrically. energized supporty and a detachable contact finger, one having an open cavity and the other having a projection pivotally seated therein whereby the finger is freely removable from its support, o 'and a single spring pressing against the contact finger adjacent its pivotal'A mounting to force the finger firmly into engagement with its support to -insure 'good electrical contact with said support, said kspring also being constructed and arranged havlng a cylindri- .concavity seating upon said fulcrum whereby the. finger for urging the finger towards its fulcrum and permitting the quick detachability of the contact'finger from its finger.

17. An electric switch having -a fulcrum, a contact finger pivotally mounted upon said fulcrum, an arm spaced from the fulcrum, anda unitary spring pressed pin device arranged to operate between the arm and finger tonormally urge the contact finger about its fulcrum, said devicehavihg opposed ends detachably socketed in the arm and finger,` respectively, whereby the same may be freely assembled in operative'positionbetween said arm and finger without disassembling the elements of the spring-device. t

18. An electric switching device having a fulcrum, a contact finger pivotally mounted upon said fulcrum and having a socket spaced from the fulcrum, an arm spaced from the fulcrum, and a resilient finger actuating means comprising a pin formed with a pintle' at one'end for tting in the finger socket and an abutment adjacent the pintle providing a spring seat and a spring encircling the pin be withdrawn from assembled `postion be tween'the arm and-finger by depressing the spring and withdrawing the devlce from the switch assembly.

In Witness whereof, .I have hereunto subscribed my name.

HERMON L. VAN VALKENBURG.

and having one end taking against the abutment, said finger actuating means being detachably interposed 'Y between the contact finger and the arm with the pintle arran ed in the socket and the spring compressed etween the arm and the abutment whereby the finger actuating means may be readily assembledl in place by merely compressing the spring and without necessitating the disassembly of any of the switch elements.

19. In an electric switch assembly having a fulcrum, a contact finger pivotally mounted to'said fulcrum and provided with a socket formed'therein, adjacent said fulcrum, a stationary arm spaced from the fulcrum and a lfinger actuating spring and ypin device mounted lbetween the fingerl and the arm, and arranged to normally urge the Afinger in one direction about the fulcrum, said device making detachable one way engagement with the stationary arm at one end and being removably arranged at its opposite end ,in said socket whereby the said device may belwithdrawn from assembled position by depressing the spring and'withdrawing the device from the arm and finger. n

20. In an electricswitch assembly having a fulcrum, a contact/finger pivotally mounted upon said fulcrum and comprising a strip o sheet metal having a portion wrapped i about the fulcrum 'to provide the pivotal connection therewith, a spring device in-` terposed between the nger and the arm for pressing the finger in one direction about its fulcrum, said spring device making detachable one way engagement with the arm and .the finger whereby the spring device may 

